Protective Efficacy of the Epitope-Conjugated Antigen N-Tc52/TSkb20 in Mitigating Trypanosoma cruzi Infection through CD8+ T-Cells and IFNγ Responses.

Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a major public health challenge affecting millions in Latin America and worldwide. Although significant progress has been made in vector control, no vaccine exists to prevent infection or mitigate disease pathogenesis. We developed a rationally designed chimeric protein vaccine, N-Tc52/TSkb20, incorporating immunodominant epitopes from two T. cruzi antigens, the amino-terminal portion of Tc52 and the TSkb20 epitope derived from trans-sialidase. The objectives of this study were to construct and characterize the antigen and evaluate its protective potential in an immunoprophylactic murine model of T. cruzi infection. The N-Tc52/TSkb20 protein was recombinantly expressed in E. coli and its identity was confirmed using mass spectrometry and Western blotting. Immunization with the chimeric protein significantly controlled parasitemia and reduced the heart, colon, and skeletal muscle parasite burdens compared to non-vaccinated mice. Protection was superior to vaccination with the individual parental antigen components. Mechanistically, the vaccine induced potent CD8+ T-cell and IFNγ responses against the incorporated epitopes and a protective IgG antibody profile. A relatively low IL-10 response favored early parasite control. These results validate the promising multi-epitope approach and support the continued development of this type of rational vaccine design strategy against Chagas disease.

Exploring the performance of Escherichia coli outer membrane vesicles as a tool for vaccine development against Chagas disease.

BACKGROUND: Vaccine development is a laborious craftwork in which at least two main components must be defined: a highly immunogenic antigen and a suitable delivery method. Hence, the interplay of these elements could elicit the required immune response to cope with the targeted pathogen with a long-lasting protective capacity. OBJECTIVES: Here we evaluate the properties of Escherichia coli spherical proteoliposomes - known as outer membrane vesicles (OMVs) - as particles with natural adjuvant capacities and as antigen-carrier structures to assemble an innovative prophylactic vaccine for Chagas disease. METHODS: To achieve this, genetic manipulation was carried out on E. coli using an engineered plasmid containing the Tc24 Trypanosoma cruzi antigen. The goal was to induce the release of OMVs displaying the parasite protein on their surface. FINDINGS: As a proof of principle, we observed that native OMVs - as well as those carrying the T. cruzi antigen - were able to trigger a slight, but functional humoral response at low immunization doses. Of note, compared to the non-immunized group, native OMVs-vaccinated animals survived the lethal challenge and showed minor parasitemia values, suggesting a possible involvement of innate trained immunity mechanism. MAIN CONCLUSION: These results open the range for further research on the design of new carrier strategies focused on innate immunity activation as an additional immunization target and venture to seek for alternative forms in which OMVs could be used for optimizing vaccine development.

Exploring the performance of Escherichia coli outer membrane vesicles as a tool for vaccine development against Chagas disease

BACKGROUND Vaccine development is a laborious craftwork in which at least two main components must be defined: a highly immunogenic antigen and a suitable delivery method. Hence, the interplay of these elements could elicit the required immune response to cope with the targeted pathogen with a long-lasting protective capacity. OBJECTIVES Here we evaluate the properties of Escherichia coli spherical proteoliposomes - known as outer membrane vesicles (OMVs) - as particles with natural adjuvant capacities and as antigen-carrier structures to assemble an innovative prophylactic vaccine for Chagas disease. METHODS To achieve this, genetic manipulation was carried out on E. coli using an engineered plasmid containing the Tc24 Trypanosoma cruzi antigen. The goal was to induce the release of OMVs displaying the parasite protein on their surface. FINDINGS As a proof of principle, we observed that native OMVs - as well as those carrying the T. cruzi antigen - were able to trigger a slight, but functional humoral response at low immunization doses. Of note, compared to the non-immunized group, native OMVs-vaccinated animals survived the lethal challenge and showed minor parasitemia values, suggesting a possible involvement of innate trained immunity mechanism. MAIN CONCLUSION These results open the range for further research on the design of new carrier strategies focused on innate immunity activation as an additional immunization target and venture to seek for alternative forms in which OMVs could be used for optimizing vaccine development.

[Carotid body paraganglioma in a teenager. Case report]. / Paraganglioma del cuerpo carotídeo en adolescente. Reporte de caso.

BACKGROUND: Paragangliomas of the head and neck are neuroendocrine tumors. They have a low incidence (0.6%), are generally benign, have a poorly defined etiology, and multiple factors have been associated with their origin. Humans and other species living at high altitudes (>2000 m above sea level) are subjected to a relatively chronic hypoxia and there is a high prevalence of the development of carotid body hyperplasia and eventually paragangliomas. This disease is usually seen in patients in their 50s and in their 30s if there is a family history. CLINICAL CASE: We present the case of a 16 year-old female with acute pharyngitis and growing tumor located on the left side of the neck, without symptoms. A duplex Doppler ultrasound showed a solid nodular lesion on the left carotid bifurcation. A left lateral cervicotomy was performed, finding a highly vascularized tumor of 4 × 3 × 3 cm involving the common carotid from its middle third, the internal carotid up to the cranial base, and the external carotid to its upper third, and intimately related to the trachea, esophagus and cervical spine. The tumor was completely resected and the histopathological analysis corroborated the presence of paragangliomas. CONCLUSIONS: The publication of this case is relevant and of clinical interest due to the uncommon age of presentation and the fact that it should be considered as a diagnostic possibility.

Antecedentes: los paragangliomas de cabeza y cuello son tumores neuroendocrinos de baja incidencia (0.6%), en su mayor parte benignos, en cuyo origen se han involucrado múltiples factores. Los seres humanos y otras especies que viven a grandes alturas (por arriba de 2000 metros sobre el nivel del mar) son propensos a sufrir hipoxia crónica relativa, hiperplasia del cuerpo carotídeo y, eventualmente, paragangliomas. Este padecimiento aparece en la quinta década de la vida y en la tercera, en caso de presentación familiar. Caso clínico: se comunica el caso de una adolescente de 16 años de edad que un año antes tuvo faringitis aguda con tumor localizado en la cara lateral izquierda del cuello, de crecimiento gradual, sin ningún síntoma. El ultrasonido Doppler dúplex de cuello mostró una lesión nodular sólida sobre el trayecto de la bifurcación carotídea izquierda. Fue intervenida quirúrgicamente mediante cervicotomía lateral izquierda, en la cual se encontró una tumoración de aproximadamente 4 × 3 × 3 cm, sumamente vascularizada, que afectaba la carótida común desde su tercio medio, la carótida interna hasta la base del cráneo y la carótida externa hasta el tercio superior, con íntima relación con la tráquea, el esófago y la columna cervical. La tumoración se resecó en su totalidad, el estudio histopatológico corroboró los paragangliomas. Conclusiones: la edad de presentación es poco común, por lo que se considera relevante y de interés clínico comunicar este caso, toda vez que debe considerarse como posibilidad diagnóstica.